Lamp power pulse modulation in color sequential projection displays

ABSTRACT

A frame sequential color display projection system ( 110 ) of this invention includes an arc lamp ( 112 ) having a predetermined power rating for providing a source of polychromatic light that propagates through a color wheel ( 120 ) that sequentially provides R, G, B, and optionally, W light colors during respective sequential time periods. A display controller ( 131 ) is synchronized with the color wheel to generate color image data during the respective time periods. A light valve, such as a DMD ( 130 ), receives the color image data for generating the frame sequential color display. A lamp ballast ( 156 ) is also synchronized with the color wheel to provide nominal and boosted power levels ( 212 ) to the arc lamp during selected ones of the time periods such that the projector provides a brighter, color-adjusted display without requiring the arc lamp to operate at an average power level exceeding its predetermined power rating.

RELATED APPLICATION(S)

Not Applicable

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

TECHNICAL FIELD

This invention relates to color sequential video and multimediaprojectors and more particularly to lamp power pulsing apparatuses andmethods for improving the projected brightness and color balance of suchprojectors.

BACKGROUND OF THE INVENTION

Projection systems have been used for many years to project motionpictures and still photographs onto screens for viewing. More recently,presentations using multimedia projection systems have become popularfor conducting sales demonstrations, business meetings, and classroominstruction.

In a common operating mode, multimedia projection systems receive analogvideo signals from a personal computer (“PC”). The video signals mayrepresent still, partial-, or full-motion display images of a typerendered by the PC. The analog video signals are typically converted inthe projection system into digital video signals that control adigitally driven image-forming device, such as a liquid crystal display(“LCD”) or a digital micro mirror device (“DMD”).

Significant effort has been invested into developing projectorsproducing bright, high-quality, color images. However, the opticalperformance of conventional projectors is often less than satisfactory.For example, suitable projected image brightness is difficult toachieve, especially when using compact portable color projectors in awell-lighted room.

Because LCD displays have significant light attenuation and triple pathcolor light paths are heavy and bulky, portable multimedia projectorstypically employ DMD displays in a single light path configuration.Producing a projected color image with this configuration typicallyrequires projecting a frame sequential image through some form ofsequential color modulator, such as a color wheel.

The use of color wheels in frame sequential color (“FSC”) displaysystems has been known for many years and was made famous (or infamous)in early attempts to develop color television sets. With technologicaladvances, however, color wheel display implementations are still usefultoday.

FIG. 1 shows the operational concept of a typical prior art FSC displaysystem 10 in which a sensor 12 senses a timing mark 14 to detect apredetermined color index position of a motor 16 that rotates a colorwheel 18 having respective red (“R”), green (“G”), and blue (“B”) filtersegments. A light source- 20 projects a light beam 22 through colorwheel 18 and a relay lens 24 onto a display device 26, such as anLCD-based light valve or a DMD. A display controller (not shown) drivesdisplay device 26 with sequential R, G, and B image data that are timedto coincide with the propagation of light beam 22 through the respectiveR, G, and B filter segments of color wheel 18. Popular commerciallyavailable color wheel-based FSC multimedia projection systems are theLP300 series manufactured by In Focus Systems, Inc., of Wilsonville,Oreg., the assignee of this application.

To improve their projected image brightness, multimedia projectionsystems typically employ a high-intensity discharge (“HID”) arc lamp,which produces a point source of intense polychromatic light that isreadily focused by a reflector onto a color wheel. HID arc lamps havemany attributes, such as high intensity, efficiency, and reliability.Unfortunately, HID arc lamps provide more light at the blue end of thespectrum than at the red end. This leads to color balance problems,which prior workers attempted to solve in various ways includingincreasing the angular extent (physical size) of the color wheel Rfilter segment relative to the B filter segment and/or increasing theattenuation of the color wheel B filter segment relative to the R filtersegment. Other workers tried reducing overall brightness levels throughcolor lookup electronics to achieve “headroom” for color adjustments.Unfortunately these “solutions” either caused temporal artifacts ordecreased image brightness.

Still other workers added a white (“W”) filter segment to the colorwheel to provide a “white peaking” function, which does increase imagebrightness albeit at a loss of color saturation. Yet others have simplyemployed more powerful arc lamps, which in compact portable projectors,leads to heat, size, weight, cost, and reliability issues.

What is needed, therefore, is a multimedia projection system having animproved technique for achieving increased image brightness, colorsaturation, and adjustable color-balance.

SUMMARY OF THE INVENTION

An object of this invention is, therefore, to provide an apparatus and amethod for improving the brightness, color saturation, and color balanceof an image projected by an FSC multimedia projector.

A frame sequential color display projection system of this inventionincludes an arc lamp having a predetermined power rating for providing asource of polychromatic light that propagates through a color wheel thatsequentially provides R, G, B, and optionally, W light colors duringrespective sequential time periods. A display controller is synchronizedwith the color wheel to generate color image data during the respectivetime periods. A light valve, such as a DMD, receives the color imagedata for generating the frame sequential color display. A lamp ballastpower supply is also synchronized with the color wheel to providenominal and boosted power levels to the arc lamp during selected ones ofthe time periods such that the projector provides a brighter displaywithout requiring the arc lamp to operate at an average power levelexceeding its predetermined power rating.

In a preferred embodiment, the color wheel includes a W filter segmentand the lamp ballast provides the boosted power level during the timeperiod when the W filter segment traverses the light source to provide aW peaking function.

In an alternative embodiment, the color wheel provides R, G, and B lightcolors during respective first, second, and third time periods, and thelamp ballast provides different power levels to the arc lamp duringpredetermined combinations of the time periods to balance the colorsdisplayed by the system.

In yet another alternative embodiment in which the arc lamp is deficientin R emission, the color wheel has R, G, and B filter segments withdifferent angular extents, and the R filter segment has a larger angularextent to compensate for the reduced R emission of the arc lamp. Thelamp ballast provides different power levels to the arc lamp duringnon-R time periods to compensate for the brightness loss resulting fromthe larger angular extent of the R filter segment.

The main advantages of this invention are that it boosts brightness orwhite peaking of an FSC projection system, enables color-balancingfunctions, and improves color saturation without resorting to higheraverage power illumination, reduced overall brightness, or decreasedcolor saturation caused by increasing the angular extent of color wheelwhite segments.

Additional objects and advantages of this invention will be apparentfrom the following detailed description of a preferred embodimentthereof that proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified pictorial diagram showing the operating principleof a prior art FSC display device employing a color wheel.

FIG. 2 is an isometric pictorial view of a preferred multimediaprojector embodiment of this invention.

FIG. 3 is a schematic block diagram of a preferred image projectionsystem of this invention showing functional inter-relationships amongelectrical, mechanical, and optical components thereof.

FIG. 4 is a simplified electrical schematic and block diagram of apulsed arc lamp ballast circuit of this invention.

FIG. 5 is a graph representing relative filtered light transmissionthrough a color wheel showing arc lamp power boost and recovery phasesof this invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 2 shows a preferred embodiment of an image projection system 110 ofthis invention that includes a high power arc lamp 112 positioned at afocus of an elliptical reflector 114 having an F-number of approximatelyF/1 to produce a high intensity illumination beam that is characterizedby a principal ray 116. Arc lamp 112 is preferably a 270 watt, highpressure mercury arc lamp, which is suitable for use in an imageprojector to achieve its lifetime and lumen specifications. The mercuryarc lamp has a nominal 1.3 mm arc gap, which contributes to highefficiency operation of the projector engine of image projection system110. The small size of the arc gap impacts the alignment of the lamp arcto the rest of the optical system and increases the importance of thestability of the arc itself. Arc lamp 112 is preferably a model SHP 270,manufactured by Phoenix, located in Himeji City, Japan,

Arc lamp 112 is positioned at the first focus of elliptical reflector114, which has a cold mirror that reflects forward only visible light.Much of the infrared and ultraviolet light is transmitted and absorbedin the housing of elliptical reflector 114. The second focus ofelliptical reflector 114 is positioned one-half the distance between thefront face of a rotating color wheel disk 118 of a color wheel assembly120 and an integrator tunnel 122. Color wheel disk 118 includes R, G,and B segments and is rotated by a motor 124 at about 5,600 to 7,500rpm, which is twice the range of system video image refresh rates, tosequentially display R, G, and B images on a projector screen (notshown). Color wheel disk 118 may also include a W (actually clear)segment that functions to increase lumens. All segments of color wheeldisk 118 carry ultraviolet reflective coatings to prevent ultravioletlight from reaching ultraviolet light sensitive components in theoptical system.

Integrator tunnel 122 creates at its output end a uniform illuminationpattern and facilitates delivering the illumination light past motor 124of color wheel assembly 120 so that motor 124 does not create a shadowin the illumination. Integrator tunnel 122 is composed of a solid glassrod that relies on total internal reflection to transfer light throughit. Integrator tunnel 122 may also include a cladding that supports theintegrator tunnel without disrupting total internal reflection. Theuniform illumination pattern of light propagating from the output end ofintegrator tunnel 122 is of rectangular shape and is imaged through lenselements 126 and 128 and a prism assembly 140 (described below) onto alight reflecting surface of a DMD 130.

DMD 130 is preferably a Texas Instruments Model DMD 1076 spatial lightmodulator composed of a rectangular array of aluminum micro mechanicalmirrors, each of which can be individually deflected at an angle of ±10degrees about a hinged diagonal axis. The deflection angle (eitherpositive or negative) of the mirrors is individually controlled by adisplay controller 131 that changes the memory contents of underlyingaddressing circuitry and mirror reset signals in DMD 130.

Illumination light exiting lens element 128 enters prism assembly 140that is comprised of a first or compensating prism 142 and a second oroutput prism component 144 that are spaced apart by an air spaceinterface 146. Prism assembly 140 allows DMD to lie flat when inoperation. Prism assembly 140 sets up the correct illumination angle onDMD 130 and separates the illumination light from the imaging lightreflected by DMD 130 in its on-state. The illumination angles for DMD130 are controlled by the angles of the faces of prism assembly 140.Prism assembly 140 refracts and reflects the incident light bundle sothat DMD 130 is illuminated from a corner with a projection angle partlybuilt into the output light bundle. After the illumination lightreflects of DMD 130 in its on-state, imaging light exits prism assembly140 along essentially the same propagation direction as that ofillumination light entering prism assembly 140. Because of the manydegrees of freedom in prism assembly 140, light can enter it roughlyparallel to a support table and in line with a projection lens 147. In apreferred case, DMD 130 is mounted to the surface of a single printedcircuit board 148 that covers the bottom of the projector. This providesa cost-effective solution because it eliminates the need for ahigh-density electrical connector otherwise required between printedcircuit board 148 and an off-board DMD.

Synchronization between the R, G, B, and W segments of color wheelassembly 120 and DMD color data generated by display controller 131 isachieved by optically detecting which color filter segment is in thelight path and for how long. Particular colors of light propagatingthrough the color wheel assembly are sensed to generate synchronizationtiming data as more fully described in allowed U.S. Pat. No. 6,155,687for LIGHT GUIDE FOR USE IN A COLOR WHEEL SYNCHRONIZATION APPARATUS ANDMETHOD, which is assigned to the assignee of this application and isincorporated herein by reference.

FIG. 3 shows the inter-relationships among the major electrical,mechanical, and optical components of image projection system 110. Inparticular, display controller 131 forms an image on DMD 130. Arc lamp112 illuminates the rotating R, G, B, and W filter segments of colorwheel assembly 120 such that principal ray 116 propagates as FSCillumination through light integrating tunnel 122, lens elements 126 and128, and prism assembly 140 to illuminate DMD 130. The FSC illuminationimpinging on DMD 130 reflects off the image formed thereon, propagatesthrough prism assembly 140 and projection lens 147 to form a projectedimage (not shown) on a projection surface 150.

Display controller 131 receives color image data from a PC 152 andprocesses the image data into frame sequential R, G, B, and W imagedata, sequential frames of which are conveyed to DMD 130 in propersynchronism with the angular position of color wheel assembly 120.Display controller 131 controls DMD 130 such that light propagating fromprism assembly 140 is selectively reflected by individual pixels withinDMD 130 either toward projection lens 147 or toward a light dump area153.

A power supply 154 powers display controller 131 and a lamp ballast 156that regulates the power delivered to arc lamp 112. Power supply 154also powers a cooling fan (not shown) and motor 124 that rotates colorwheel assembly 120. Motor 124 rotates color wheel assembly 120 at about6,650 to 7,500 rpm depending on the frame rate of the color image datareceived from PC 152 by display controller 131. Color wheel assembly 120preferably includes R, G, W, and B filter segments that surroundrespective 119°, 104°, 40°, and 97° sectors of color wheel assembly 120.

Synchronization of the FSC data driving DMD 130 to the rotational angleof color wheel assembly 120 is achieved by optically detecting whichfilter segment color is intersecting principal ray 116 and for how long.Particular colors of light propagating through color wheel assembly 120are sensed to generate synchronization timing data. In particular, somestray light rays reflected by reflector 114 propagate through colorwheel assembly 120 at locations adjacent to integrator tunnel 122. Tocollect some of these stray rays, a light guide 158 is positionedadjacent to integrator tunnel 122. Light guide 158 has a slanted outputend 160 that reflects the stray rays toward a photo detector 162 thatconveys the timing data to display controller 131.

FIG. 4 shows lamp ballast 156 in more detail. In particular, lampballast 156 includes a conventional lamp igniter circuit 170,pulse-width-modulator (“PWM”) controller 172, switching transistor 174,current sense resistor 176, and filter network 178 that coact to supply50 to 100 volts DC at a nominal 3.6 amperes to arc lamp 112 after it isignited. Current sense resistor 176 preferably comprises two 0.33 ohmresistors connected in parallel. Lamp ballast 156 also includesconventional over-voltage, open-, and short-circuit detectors 180.

PWM controller 172 operates in a power regulation control loop thatincludes a current limiter 182 and reference buffer amplifier 184 thatcondition and couple the “drive” signal operating switching transistor174 to the non-inverting input of a power-error integrator 186. Acurrent sense signal developed across current sense resistor 176 iscoupled to the inverting input of power-error integrator 186. The loopis closed by connecting the output of power-error integrator 186 to a“multiplier” input of PWM controller 172. The regulation control loop isbalanced when the average drive signal coupled to power-error integrator186 equals the average current sense signal coupled from current senseresistor 176. PWM controller 172 further includes a “sense” input forregulating the magnitude of the drive signal in response to theinstantaneous current sensed across current sense resistor 176.

The amount of power delivered by switching transistor 174 to arc lamp112 is controllable as follows. The amount of drive signal coupled fromcurrent limiter 182 and reference buffer amplifier 184 to power-errorintegrator 186 is adjustable by a voltage divider comprising a variableresistor 188 and a fixed resistor 190. Decreasing the effective value ofvariable resistor 188 increases the power to arc lamp 112. Variableresistor 188 is adjusted to establish a nominal low power setting forlamp ballast 156. Also, the amount of drive signal coupled from currentlimiter 182 and reference buffer amplifier 184 to power-error integrator186 is further increased by employing an opto-isolator 192 to switch aresistor 194 in parallel with variable resistor 188. Opto-isolator 192receives a signal from display controller 131 for switching lamp ballast156 between the nominal low power setting and a nominal high powersetting. Switchable power settings are useful when transitioning throughthe below-described arc lamp 112 ignition, warmup, and sustainedoperation periods.

Lamp igniter circuit 170 generates greater than 10,000 volt pulses,preferably 20,000 volt pulses, during the ignition of arc lamp 112. Oncean arc is established, the gas in the arc lamp 112 begins to ionize. Asgas ionization continues, the arc voltage gradually increases along withthe lamp temperature until arc lamp 112 reaches its full operatingtemperature after about two minutes. During this initial start-up periodlamp ballast 156 preferably operates at the low power setting to preventdamage to the electrodes in arc lamp 112. As the temperature of arc lamp112 increases, it draws more current. Once arc lamp 112 reaches fullpower, lamp ballast 156 is switched to operate at the high power settingand provides a substantially constant current and power to arc lamp 112.

Prior workers have pulsed the power delivered to arc lamps for arcstabilization purposes. However, unlike prior workers, applicants havediscovered that the lumens, delivered by arc lamp 112 and focusedthrough a 6 mm aperture, increases linearly with power. In particular,at 350 watts, arc lamp 112 delivers about 33 percent more lumens than at250 watts. Applicants reasoned that the ability to rapidly change theluminous output of arc lamp 112 in a controlled manner could be used toadjust color balance, white peaking, and color saturation of FSCmultimedia projectors, such as image projection system 110 (FIGS. 2 and3).

However, the response time of the above-described power settingtechniques is relatively slow because of long time-constant filtering incurrent limiter 182 and power-error integrator 186. Faster power settingresponse is required if lamp power changes are to be synchronized withthe rotation of color modulation devices, such as color wheel 120.

Faster responding power control is achieved by controlling the amount ofcurrent sense signal coupled from current sense resistor 176 through aresistor 196 to the sense input of PWM controller 172. The amount ofcoupling is, preferably, attenuated by employing an opto-isolator 198 toswitch a transistor 200 between on and off states, thereby shunting aportion of the current sense signal through a resistor 202 andtransistor 200 to ground. Resistors 196 and 202 have respective 500 and1,000 ohm values such that when transistor 200 is in its on state, thecurrent sense signal coupled to PWM controller 172 is reduced by about33 percent, and the power delivered to arc lamp 112 increases from about260 watts to about 350 watts. Of course various other techniques forchanging the current sense signal coupling may be employed, such as gaincontrolled amplification, switchable current sense resistors, and gainDACs. Digital or analog control techniques may be employed.

Preferably, however, opto-isolator 198 receives a power pulse signalfrom display controller 131 for switching lamp ballast 156 between thenominal 260 watt high power setting and the boosted 350 watt powersetting during the time when the W filter segment is traversingprincipal ray 116. The power delivered to arc lamp 112 switches betweenthe high and boosted settings in about 50 to 100 microseconds. Thisswitching time is limited mainly by the ripple filtering components offilter network 178, but is, nevertheless, suitable for use in thisinvention as described below.

FIG. 5 represents the relative amounts of filtered light transmitted bythe R, G, B, and W filter segments of color wheel assembly 120 as itrotates through a 360 degree rotation. A solid line 210 represents therelative light transmission with color wheel assembly 120 illuminated bya constant light source, whereas a dashed line 212 represents therelative light transmission with color wheel assembly 120 illuminated bypulsing arc lamp 112 in accordance with the preferred embodiment of thisinvention. In the embodiment shown by dashed line 212, the power to arclamp 112 is set to the nominal 260 watt high power setting during the320 degree rotation of the R, G, and B filter segments through principalray 116 and is boosted to the 350 watt setting during the 40 degreerotation of the W filter segment through principal ray 116. The averagepower delivered to arc lamp 112 is, thereby, maintained at its 270 wattrated level over each complete rotation of color wheel assembly 120.

The power modulation is preferably implemented such that a color wheelrotation period is subdivided into at least one boosted power phase anda reduced power recovery phase. Display controller 131 employs photodetector 162 to detect when at least one of the R, G, B, and W filtersegments of color wheel assembly 120 are traversing principal ray 116,and switches lamp ballast 156 between the high and boosted powersettings at the correct time(s). The high and boosted power levels andfilter segment angular extents are designed to maintain the averagepower to arc lamp 112 at its rated levels. Two possible color wheelimplementations employing the same power switching levels, but differentR, G, and B filter segment angular extents are shown below in Table 1.

TABLE 1 Segment Lamp Power Degrees Preferred Degrees W 350 40 40 R 260106.67 119 G 260 106.67 104 B 260 106.67 97

The rotational period of color wheel assembly 120 is dependent on theincoming video refresh rate, and ranges between 8.06 msec and 10.7 msecper revolution. Therefore, each degree of rotation takes at least 22.4microseconds, and the 40 degree W filter segment requires 896microseconds to traverse principal ray 116. Accordingly, the 50-400microsecond brightness rise time resulting from lamp ballast 156 pulsingarc lamp 112 is suitable for use with this invention.

A FSC projector incorporating either of the Table 1, color wheelembodiments is advantageous because it maintains the rated 270 Watts ofaverage arc lamp power while providing more total light transmission(lumens) through color wheel assembly 120 because additionalillumination is transmitted through the W segment without increasing itsangular extent at the expense of the R, G, and B filter segments.

Alternative embodiments to lamp ballast 156 may include multipleswitchable power amplitudes to accommodate finer control of the amountof light transmitted through each of the R, G, B, and (optional) Wfilter segments. The resultant luminance modulation, as a function ofselected color phase, can be used in the following alternativeembodiments:

1. Boosted illuminance can be associated with the W filter segment in anRGBW FSC system to boost total luminance output. This is referred to as“brightness peaking” or “white peaking”

2. Boosted illuminance can be associated with multiple W color wheelspoke transition segments in an RGBW color sequential system to boosttotal luminance output.

3. Boosted illuminance can be associated with a selected one of the R,G, and B color filter segments in a FSC system to boost luminance outputfor the selected color filter segment relative to the other color filtersegments to control color balance independently of any gray scale imagecapability. This embodiment further enables:

-   -   -   a. Low luminance component color filter segments to be            decreased in angular extent at boosted illuminance, levels,            and high luminance component color filter segments to be            increased in angular extent at reduced luminance levels,            resulting in more effective distributions of the time            sequential pulse width modulation bits driving DMD 130.        -   b. Low luminance component color filter segments to be            decreased in angular extent at boosted illuminance levels,            and high luminance component color filter segments to be            increased in angular extent at reduced luminance levels,            resulting in improved color balance with increased luminance            output.

For example, the preferred embodiment represented by dashed line 212 ofFIG. 5, the R filter segment spans 119 degrees, whereas the G and Bfilter segments respectively span only 104 and 97 degrees. This improvescolor balance and saturation by compensating for the reduced emission ofarc lamp 112 at the red end of the spectrum and for the reduced need forblue brightness in many images. However, in this example lamp powerboosting is applied only during passage of the W filter segment.

As a guide, the average power delivered to arc lamp 112 during onecomplete rotation of color wheel assembly 120 can be calculated byemploying the following equation:Avg Pwr−={(reduced pwr*degrees)+(boosted pwr*degrees)}/360Of course, the equation can be solved for any of the variables if theother variable are known, such as the rated power of arc lamp 112 and,for example, the 40 degree extent of the W filter segment. Variousworkable combinations of reduced and boosted power levels and filtersegment angles can, thereby, be derived.

Skilled workers will recognize that portions of this invention may beimplemented differently from the implementations described above for apreferred embodiment. For example, color wheel assembly 120 may includea different filter segment order, different colors, no white segment,and may be a color modulator other than a color wheel. DMD 130 may beone of many different light valve types, such as LCD, transmissive, orreflective types incorporated in a variety of different optical engines,some without a prism, a fly's eye lens integrator instead of anintegrator tunnel, and different color wheel sync techniques, such ascommutators, reflective strips, and optical sensors.

It will be obvious to those having skill in the art that many changesmay be made to the details of the above-described embodiments of thisinvention without departing from the underlying principles thereof. Thescope of this invention should, therefore, be determined only by thefollowing claims.

We claim:
 1. In a method for color balancing a display generated by a frame sequential color display system including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the first and second time periods at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness.
 2. The method of claim 1, in which the color display system is a projection display system.
 3. The method of claim 1, in which the color modulator is a color wheel and at least the first and second light colors are produced by filtering the polychromatic light with corresponding color wheel filter segments selected from a red filter segment, a green filter segment, a blue filter segment, and a white filter segment.
 4. The method of claim 1, in which the second light color is white.
 5. The method of claim 1, in which the second light color is red.
 6. The method of claim 1, further including a third light color and a third time period, and in which the color modulator sequentially propagates the first, second, and third light colors during respective first, second, and third time periods, the method further comprising driving the arc lamp during the third time period at a power level that is less than the arc lamp power rating.
 7. The method of claim 1, in which the polychromatic light includes unequal amounts of red, green, and blue light and in which the color modulator sequentially propagates at least red, green, and blue light colors during respective first, second, and third time periods having predetermined durations that compensate for the unequal amounts of red, green, and blue light produced by the arc lamp.
 8. The method of claim 7, in which the color modulator is a color wheel having filter segments and in which the predetermined durations are determined by red, green, and blue filter segments having angular extents corresponding to the predetermined durations.
 9. The method of claim 8, in which at least two of the angular extents are unequal.
 10. The method of claim 1, in which the first light color includes at least one color selected from the group consisting of red, green, and blue, the second light color includes a boosted color, and a red time period is greater than a blue time period, which is greater than a boosted color time period.
 11. The method of claim 1, in which the first light color includes at least one color selected from the group consisting of red, green, and blue, the second light color includes a boosted color, and a red time period is greater than a green time period, which are both greater than a boosted color time period.
 12. The method of claim 1, in which the first light color includes at least one color selected from the group consisting of red, green, and blue, the second light color includes a boosted color, and a green time period is greater than a blue time period, which is greater than a boosted color time period.
 13. The method of claim 1, in which the first light color includes at least one color selected from the group consisting of red, green, and blue, the second light color includes a boosted color, and a red time period is greater than a boosted color time period, a green time period is greater than the boosted color time period, and a blue time period is greater than the boosted color time period.
 14. The method of claim 1, in which the second light color is a color selected from the group consisting of red, green, and blue, the first light color is at least one color selected from the group consisting of red, green and blue excluding the second light color, and the second time period is shorter than the first time period.
 15. The method of claim 1, in which the second light color is a color selected from the group consisting of red, green, blue and white, the first light color is at least one color selected from the group consisting of red, green, blue and white excluding the second light color, and the second time period is shorter than the first time period.
 16. The method of claim 1, in which the second light color is white, the first light color is at least one color selected from the group consisting of red, green and blue, and the second time period is shorter than the first time period.
 17. The method of claim 1, in which the second light color includes a boosted color, the boosted color is white, a color wheel is selected as the color modulator, and the color wheel is configured to include a white segment that spans substantially 40 degrees of the color wheel.
 18. The method of claim 1, in which the first light color includes at least one color selected from the group consisting of red, green, and blue, the second light color includes a boosted color, a red time period is provided before a green time period, the green time period is provided before a boosted color time period, and the boosted color time period is provided before a blue time period, in a color rotation.
 19. The method of claim 1, in which the first light color includes at least one color selected from the group consisting of red, green, and blue, the first time period includes at least one time period selected from the group consisting of a red time period, a green time period and a blue time period, the second time period includes a transition period from the green period to the blue period.
 20. The method of claim 1, a color wheel is selected as the color modulator, and the color wheel is configured to include a red segment, a green segment, a blue segment, and a boosted color segment, the boosted color segment being arranged between the blue and green segment.
 21. The method of claim 1, a color wheel is selected as the color modulator, and the color wheel is configured to include a red segment, a green segment, a blue segment, and a boosted color segment, the boosted color segment being a a plurality of transition segments that are arranged between the red segment and green segment, between the green segment and blue segment, and between the blue segment and red segment.
 22. The method of claim 1, in which a difference between the boosted power level and arc lamp power rating is greater than a difference between the low power level and the arc lamp power rating.
 23. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during and throughout respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during and throughout the first time period at less than the arc lamp power rating and driving the arc lamp during and throughout the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during and throughout the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during and throughout the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during and throughout the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during and throughout the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness, wherein the second time period is shorter than the first time period.
 24. The method of claim 23, in which the color display system is a projection display system.
 25. The method of claim 23, in which the color modulator is a color wheel and at least the first and second light colors are produced by filtering the polychromatic light with corresponding color wheel filter segments selected from a red filter segment, a green filter segment, a blue filter segment, and a white filter segment.
 26. The method of claim 23, in which the second light color is white.
 27. The method of claim 23, in which the second light color is red.
 28. The method of claim 23, further including a third light color and a third time period within the frame cycle, and in which the color modulator sequentially propagates the first, second, and third light colors during and throughout respective first, second, and third time periods, the method further comprising driving the arc lamp during and throughout the third time period at a power level that is less than the arc lamp power rating.
 29. The method of claim 23, in which the polychromatic light includes unequal amounts of red, green, and blue light and in which the color modulator sequentially propagates at least red, green, and blue light colors during and throughout respective first, second, and third time periods having predetermined durations that compensate for the unequal amounts of red, green, and blue light produced by the arc lamp.
 30. The method of claim 29, in which the color modulator is a color wheel having filter segments and in which the predetermined durations are determined by red, green, and blue filter segments having angular extents corresponding to the predetermined durations.
 31. The method of claim 30, in which at least two of the angular extents are unequal.
 32. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during and throughout respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during and throughout the first time period at less than the arc lamp power rating and driving the arc lamp during and throughout the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during and throughout the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during and throughout the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during and throughout the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during and throughout the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness, wherein, for each frame cycle, the arc lamp is operated above the arc lamp power rating for a shorter period of time than the arc lamp is operated below the arc lamp power rating.
 33. The method of claim 32, in which the color display system is a projection display system.
 34. The method of claim 32, in which the color modulator is a color wheel and at least the first and second light colors are produced by filtering the polychromatic light with corresponding color wheel filter segments selected from a red filter segment, a green filter segment, a blue filter segment, and a white filter segment.
 35. The method of claim 32, in which the second light color is white.
 36. The method of claim 32, in which the second light color is red.
 37. The method of claim 32, further including a third light color and a third time period within the frame cycle, and in which the color modulator sequentially propagates the first, second, and third light colors during and throughout respective first, second, and third time periods, the method further comprising driving the arc lamp during and throughout the third time period at a power level that is less than the arc lamp power rating.
 38. The method of claim 32, in which the polychromatic light includes unequal amounts of red, green, and blue light and in which the color modulator sequentially propagates at least red, green, and blue light colors during and throughout respective first, second, and third time periods having predetermined durations that compensate for the unequal amounts of red, green, and blue light produced by the arc lamp.
 39. The method of claim 38, in which the color modulator is a color wheel having filter segments and in which the predetermined durations are determined by red, green, and blue filter segments having angular extents corresponding to the predetermined durations.
 40. The method of claim 39, in which at least two of the angular extents are unequal.
 41. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle each available light color being propagated for a respective color time period, the frame sequential color display system further including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness, wherein the first color includes at least one color selected from the group consisting of red, green and blue, the second color includes a boosted color, and a red color time period is greater than a blue color time period, which is greater than a boosted color time period.
 42. The method of claim 41, in which the boosted color is white.
 43. The method of claim 42, in which a color wheel is selected as the color modulator, and the color wheel is configured to include a white segment that spans substantially 40 degrees of the color wheel.
 44. The method of claim 41, in which the first light color includes red, green, and blue.
 45. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle each available light color being propagated for a respective color time period, the frame sequential color display system further including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness; wherein the first color includes at least one color selected from the group consisting of red, green and blue, the second color includes a boosted color, and a red color time period is greater than a green color time period, which is greater than a boosted color time period.
 46. The method of claim 45, in which the boosted color is white.
 47. The method of claim 46, in which a color wheel is selected as the color modulator, and the color wheel is configured to include a white segment that spans substantially 40 degrees of the color wheel.
 48. The method of claim 45, in which the first light color includes red, green, and blue.
 49. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle each available light color being propagated for a respective color time period, the frame sequential color display system further including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness; wherein the first color includes at least one color selected from the group consisting of red, green and blue, the second color includes a boosted color, and a green color time period is greater than a blue color time period, which is greater than a boosted color time period.
 50. The method of claim 49, in which the boosted color is white.
 51. The method of claim 49, in which the boosted color is red.
 52. The method of claim 50, in which a color wheel is selected as the color modulator, and the color wheel is configured to include a white segment that spans substantially 40 degrees of the color wheel.
 53. The method of claim 49, in which the first light color includes red, green, and blue.
 54. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle each available light color being propagated for a respective color time period, the frame sequential color display system further including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness; wherein the first color includes at least one color selected from the group consisting of red, green and blue, the second color includes a boosted color, and a red color time period is greater than a boosted color time period, a green color time period is greater than the boosted color time period, a blue color time period is greater than the boosted color time period.
 55. The method of claim 54, in which the boosted color is white.
 56. The method of claim 55, in which a color wheel is selected as the color modulator, and the color wheel is configured to include a white segment that spans substantially 40 degrees of the color wheel.
 57. The method of claim 54, in which the first light color includes red, green, and blue.
 58. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness; wherein. the second light color is one color selected from the group consisting of red, green and blue, the first light color is at least one color selected from the group consisting of red, green, and blue excluding the second light color, and the second time period is shorter than the first time period.
 59. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness; wherein the second light color is one color selected from the group consisting of one of red, green, blue and white, the first light color is at least one color selected from the group consisting of one of one of red, green, blue and white excluding the second light color, and the second time period is shorter than the first time period.
 60. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness; wherein the second light color is white, the first light color is at least one color selected from the group consisting of one of red, green, and blue, and the second time period is shorter than the first time period.
 61. The method of claim 60, in which a color wheel is selected as the color modulator, and the color wheel is configured to include a white segment that spans substantially 40 degrees of the color wheel.
 62. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve in the form of a DMD made of an array of micro mirrors that are switched based on time sequential pulsed width modulation bits, the light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness; wherein the second time period is longer than a brightness rise time, wherein the brightness rise time is a time necessary for the arc lamp to change power levels, and the second time period is longer than the pulse width modulation bits driving the DMD.
 63. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness; wherein the second color includes a boosted color, the boosted color being white, and the color modulator being a color wheel configured with a white segment that contains substantially 40 degrees of the color wheel.
 64. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle each available light color being propagated for a respective color time period, the frame sequential color display system further including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness; wherein the first light color includes at least one color selected from the group consisting of red, green, and blue, the second light color includes a boosted color, and a red color time period is provided in advance of a green color time period, the green color time period is provided in advance of a boosted color time period, the boosted color time period is provided in advance of a blue color time period, in a color rotation.
 65. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle each available light color being propagated for a respective color time period, the frame sequential color display system further including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness; wherein the first color includes at least one color selected from the group consisting of red, green and blue, the first time period includes at least one time period selected from the group of a red color time period, a green color time period, and a blue color time period, and the second time period includes a transition period from the green color time period to the blue color time period.
 66. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness; wherein the color modulator is selected to be a color wheel, the color wheel is configured with a red segment, a green segment, a blue segment, and a boosted color segment, and the boosted color segment is arranged between the green segment and the blue segment.
 67. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness; wherein the color modulator is selected to be a color wheel, the color wheel is configured with a red segment, a green segment, a blue segment, and a boosted color segment, and the boosted color segment is a plurality of transition segments that are arranged between the red segment and green segment, between the green segment and blue segment, and between the blue segment and red segment.
 68. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a low power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness, wherein a first difference between the boosted power level and the arc lamp power rating is greater than a second difference between the low power level and the arc lamp power rating.
 69. The method of claim 68, in which a difference between the boosted power level and the low power level is substantially equal to 33 percent of the arc lamp power rating.
 70. The method of claim 68, in which a difference between the boosted power level and the low power level is substantially equal to 90 watts.
 71. The method of claim 68, in which a difference between the low power level and the arc lamp power rating is substantially equal to 3.7 percent of the arc lamp power rating.
 72. The method of claim 68, in which a difference between the low power level and the arc lamp power rating is substantially equal to 10 watts.
 73. The method of claim 41, in which a difference between the boosted power level and the arc lamp power rating is substantially equal to 30 percent of the arc lamp power rating.
 74. The method of claim 68, in which a difference between the boosted power level and the arc lamp power rating is substantially equal to 80 watts.
 75. In a method for color balancing a display generated by a frame sequential color display system that sequentially propagates a predetermined number of available light colors within a frame cycle including an arc lamp having a power rating and providing polychromatic light including different amounts of a first light color and a second light color, a color modulator receiving the different amounts of light colors and propagating the first and second light colors during respective first and second time periods within the frame cycle, a display controller generating first and second image data during the respective first and second time periods, a light valve generating the display in response to receiving the first and second light colors and the first and second image data during the first and second time periods, a lamp ballast driving the arc lamp during the first time period at less than the arc lamp power rating and driving the arc lamp during the second time period at the arc lamp power rating such that the arc lamp operates at an average power level that is less than the arc lamp power rating to color balance the display by reducing an arc lamp brightness during the first time period, thereby reducing an average brightness of the display, an improvement comprising: driving the arc lamp during the first time period at a power level that is less than the arc lamp power rating; and driving the arc lamp during the second time period at a boosted power level that is greater than the arc lamp power rating, such that the arc lamp operates during the frame cycle, which includes the first and second time periods, at an average power level that substantially equals the arc lamp power rating and the display is color balanced by boosting the arc lamp brightness during the second time period and reducing the arc lamp brightness during the first time period without reducing the display average brightness; wherein the color modulator is configured to produce a red, green, blue, and white colored light, and the second time period includes a time during which the white colored light and one of the red, green and blue lights are transmitted. 